Summaries for Patients|19 June 2012

Acute Liver Injury due to Flavocoxid (Limbrel), a Medical Food for Osteoarthritis

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The full report is titled “Acute Liver Injury due to Flavocoxid (Limbrel), a Medical Food for Osteoarthritis. A Case Series.” It is in the 19 June 2012 issue of Annals of Internal Medicine (volume 156, pages 857-860). The authors are N. Chalasani, R. Vuppalanchi, V. Navarro, R. Fontana, H. Bonkovsky, H. Barnhart, D.E. Kleiner, and J.H. Hoofnagle, on behalf of the Drug-Induced Liver Injury Network.

What is the problem and what is known about it so far?

Flavocoxid is a prescription-only blend of plant compounds that may be used to treat arthritis. It is classified by the U.S. Food and Drug Administration as a “medical food,” a term used for nutritional supplements that are intended for use in managing specific diseases or conditions under medical supervision. Unlike drugs, compounds classified as medical foods are not required by the U.S. Food and Drug Administration to undergo formal safety and effectiveness testing before going on the market.

Flavocoxid's product label states that the compound has few adverse effects and that clinical trials have shown it to be as safe as a placebo, but the specific effects of flavocoxid on the liver are unknown. No published reports have linked liver injury to flavocoxid since it became available in 2004.

Why did the researchers do this particular study?

To describe a series of patients who developed liver problems while taking flavocoxid.

Who was studied?

4 adults with liver injury suspected of being caused by flavocoxid.

How was the study done?

A network of 8 clinical centers and 1 data coordinating center enrolled 877 patients with suspected drug-induced liver injury between 2004 and 2010. They collected serum, urine, and DNA for laboratory studies as well as other medical information on each patient, and they assessed the possible causes of the liver injury.

What did the researchers find?

Four of the patients had liver injury that was due, at least in part, to the use of flavocoxid. All were women ranging in age from 57 to 68 years who were taking the supplement in doses of 250 to 500 mg twice daily for arthritis or musculoskeletal pain symptoms. Within 1 to 3 months after starting flavocoxid, the patients developed signs and symptoms of liver injury, including jaundice, abdominal pain, fever, itching and rash, and elevations in serum liver enzyme levels. Results of tests for other causes of liver injury were negative. The liver injury began to resolve within a few days after stopping flavocoxid, and serum enzyme levels decreased to normal within 1 to 3 months. There was no evidence of ongoing or chronic liver injury.

The researchers determined that flavocoxid was the cause of the liver injury in 3 patients and the possible cause in 1 patient. The cause of the liver injury was undetermined in the possible case because the patient was taking other medications in addition to flavocoxid.

What were the limitations of the study?

The researchers could assess only these 4 cases. The frequency, risk factors, and mechanisms of liver injury due to flavocoxid are unknown.

What are the implications of the study?

Flavocoxid is capable of causing acute liver injury and should be used with caution. Stopping the medication reverses the adverse effect.

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